How do i add a transparent texture over my material?
Here - This is a common setup for mixing 2 textures (especially rust, as the noise texture works well to create random &quot;rusty patches, however I used concrete here). You can also use your own texture (if it has a built in alpha, connect as shown). Sometimes as well, texture packs come with alpha &quot;masks&quot; that are their own separate texture. You connect these as a factor the same way. Ultimately, any B&amp;W image can be used as a mix factor. Play around to get what you like. See below:
This is all done on one plane with only one face.

Also, it's a bit hard to follow what you were doing with the roughness thing, however, if you have a roughness map, and want to apply it &quot;correctly&quot;, mix the maps together with the same mix factor.